Master Thesis Defense by Esben Skovhus Ditlefsen

Title: Mass spectrometer measurements of oxygen

Abstract:
Molecular oxygen makes up a large portion of the atmosphere. Oxygen plays an important role in both the biosphere and atmospheric chemistry. Studying the isotopic composition of gaseous oxygen trapped in ice cores informs us about these processes back in time. An emerging subject is the study of clumped isotopes i.e. molecules with more than one rare isotope. Clumped oxygen has the potential to be a useful proxy for methane removal through oxidation. Initial measurements to investigate the stability and accuracy of a new mass spectrometer has been performed. An extraction system for oxygen has been restored and improved. Full automation has been made possible and possibility of removing argon, necessary to measure clumped oxygen, has been investigated. Preliminary results on gas samples collected from firn close to the NEEM drill site in 2008.

Supervisor: Thomas Blunier